Environmental Earth Sciences

The potential extent of desertification in China (PEDC), composed by arid, semi-arid and dry sub-humid regions, was re-determined using a high spatial resolution meteorological dataset (1981–2010) and by applying the Thornthwaite method, which was recommended by the UNCCD for division of dryland zones (extremely arid, arid, semi-arid, dry sub-humid zones). The dynamic and the dry/wet trends in climatic variation in the general PEDC during 1981–2010 were statistically analyzed using several different methods. The newly calculated area of the general PEDC is approximately 3.222 × 106 km2, accounting for 33.6 % of China’s terrestrial. However, the results of a decadal spatial analysis indicated that the actual reduction appeared in the western region, where the general PEDC shrank to lower altitude areas. Meanwhile, the eastern border of the general PEDC was expanded to the east and southeast. Over three decades, the lower mountainous areas in northwestern Qinghai-Tibetan Plateau have experienced an obviously alternating process of drought–wetness–drought, the semi-arid and dry sub-humid regions in the east of the Helan Mountains as well as the Junggar Basin have experienced an alternating process of wetness–drought–wetness, and the vast arid region in the west of the Helan Mountains has experienced a process of drought–drought–wetness. In the most recent decade, most areas, except for the major western mountainous regions, have been experiencing a wet trend, which is favorable for combating desertification.